The disastrous Animas River spill that threatens the water supply in southwestern Colorado, northwestern New Mexico and northeastern Arizona reinforces the value of harvesting rainwater to provide distributed sources of safe water. Ironically, it is illegal to collect rainwater in Colorado unless you have a residential well permit and you do not have access to municipal water. New Mexico and Arizona have no such restrictions.

A well-designed, installed and maintained rainwater harvesting system can provide significant amounts of high-quality water for potable and non-potable, residential and commercial use. Even in the arid Four Corners area of this spill, ample water can be harvested. Given this area's 10-inch annual precipitation, a 1,500-square-foot residential roof could collect over 9,000 gallons annually. A commercial roof of 100,000 square feet could collect 600,000 gallons annually. Attesting to the quality of rainwater, former ARCSA board member Jack Holmgreen won a Gold Medal for his rainwater entry in the 2011 Berkeley Springs International Water Tasting competition.

There is a  long list of chemicals that includes perchlorate (rocket fuel), MTBE (an automobile fuel additive), ethylene glycol (anti-freeze), MEK (solvent) and formaldehyde, for which there are no EPA drinking-water limits. That 's right, as unbelievable as it sounds, any amount can be in your drinking water without exceeding the  EPA Drinking Water standards.

The Environmental Working Group has identified over  200 contaminants in the nation 's drinking water for which there are no limits, which is one reason the ancient practice of collecting, treating and using rainwater is being revived with modern techniques and materials.